Knee joint locking device



June 27, 1950 v M, CLARK 2,512,826,

KNEE JOINT LOCKING DEVICE v Filed Marhas, 1948 Moriqn Clark INVENTOR I I 1 BY I I l I ATTORNEYS.

Patented June 27, 1950 UNITED STATES PATENT OFFICE KNEE JOINT LOCKING DEVICE Morton Clark, La J olla, Calif.

Application March 23, 1948, Serial No. 16,417

1 Claim.

This invention relates to metal leg braces, and more particularly, has reference to a knee joint locking device for a device of this type.

When a metal leg brace is worn, it is usually necessary that it be rigid from top to bottom when weight is placed on the leg, this being, understandably, thebasic purpose of such a brace. However, when the wearer is walking, or sits down, it is desirable that the knee joint of the brace be permitted to flex, since on these occasions, the weight has been taken oii the leg, and it is not necessary for the moment that the brace be rigid.

In the past, braces have been manufactured which for the most part are rigid at all times, these sometimes being provided with manually controlled knee locks.

The primary object of the present invention i to provide, in a, brace of the type stated, a knee joint locking device which acts automatically, when weight is taken oil the foot, to permit flexing of the brace, and which looks the upper and lower sections of the brace rigidly together when weight is again placed on the foot or leg.

Another important object is to provide, in a device of the general character described, a simple and yet efilcient construction, that will not readily get out of order, and which is capable of being manufactured at reasonable costs.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts, hereinafter more fully described and pointed out in the claim, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

Referring to the drawing Figure 1 is a side elevational view of my looking device, applied to a leg brace, portions being broken away, the device being shown in looking position.

Figure 2 is an edge elevational view, portions being broken away.

Figure 3 is an enlarged longitudinal section through the device and the brace to which it is attached, portions being broken away and other parts remaining in elevation, the device being shown in unlocked osition, when weight is taken off the leg.

Referring to the drawing in detail, 5 designates padding, preferably leather covered, that fits the crotch, and which is secured to the upper end of an upper brace section 6 having the leather thigh strap 1. The lower brace section is designated 8, and is formed with a slotted upper end, as at 9, to receive the lower end of the upper section 6, and the two sections are pivotally joined by a pivot bolt II].

An opening I I is formed in the lower brace section 8, and communicates with slot 9 through the bottom thereof. A lock pin l2, having a pointed inner end I3, is slidably mounted in the opening, and when weight is placed on the leg, is normally positioned inside the slot 9.

The bottom of the upper brace section 6 isprovided with a conical recess 14, adapted to receive the tapered or pointed end l3 of the lock pin. When the tapered end [3 is positioned inside recess l4, it is observed that the upper and lower brace sections will be rigidly locked as in Figures 1 and 2.

Fixed to the outer end of lock pin I 2 is one end of a flexible steel cable l5, that is slidable in the flexible housing Hi. The flexible housing extends along one side of the lower brace section 8, and is spot welded thereto a at I! and "3, although other suitable fastening means could also be used.

At the lower end of the lower brace section 8, a tubular member I9 is fixedly secured thereto as by spot weld 20, and the lower end of the flexible housing is extended into this tube. A shaft 2! is slidable in the tubular member, and at its upper end is secured to the lower end. of the cable l5. Shaft 2| projects below the tubular member, and at its lower end is secured to a trigger or cap 22 which may be of resilient rubber material or the like. A spring 23 is interposed between the trigger and the lower end of the tubular member 19, and surrounds the shaft 2|. When weight is on the leg of the wearer, spring 23 is held under compression.

The wearers shoe is designated S, and i provided with a heel H to which the lower end of the brace section 8 is secured fixedly.

I believe that the operation of my device will be apparent. As may be noted from Figure 3, when the heel H is lifted olT the ground or other supporting surface, spring 23 is free to expand and causes the trigger 22 to be disposed in a slightly lower plane than the heel. The extent of expansion of the spring is limited by the fact that the upper end of the flexible housing It constitutes a stop, as shown at 24, for the lock pin I2.

By reason of expansion of the spring, the pin I2 is withdrawn from recess l4, and the brace is accordingly permitted to flex at the knee. The

brace is automatically freed for flexing, accordingly, whenever a step is taken or whenever the wearer desires to sit down. In the latter case, it is necessary only that the wearer lift his shoe slightly off the floor.

Whenever weight is again placed on the leg, spring 23 is compressed, and the tapered end I3 of the lock pin again enters the recess 14, looking the upper and lower brace sections rigidly together.

What is claimed is:

In a leg brace, pivotally connected upper and lower brace sections, a lock pin mounted for up and down sliding movement in the lower brace,

section and adapted when moved upwardly to engage the upper section to hold the sections. against relative movement, a cable. slidably mounted upon the lower section and extended longitudinally thereof, the cable being secured at its upper end to the lock pin, a cap on the lower Number Name Date 62,731 Carleton Mar. 12, 1867 911,243 Johannesen Feb. 2, 1909 1,302,338 Ernst Apr. 29, 1919 1,338,155 Pringle Apr. 27, 1920 20 2,485,036 Christopher Oct. 18, 1949 4 end of the cable, and a compression spring interposed between the cap and lower brace section, said cap being positioned to engage the ground and being moved by the spring to a position below the bottom of the shoe of a wearer when said shoe is elevated above the ground.

MORTON CLARK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

